We examined evidence regarding the influence of school physical environment on healthy-eating outcomes. We applied a systems perspective to examine multiple disciplines' theoretical frameworks and used a mixed-methods systematic narrative review method, considering both qualitative and quantitative sources (published through March 2014) for inclusion. We developed a causal loop diagram from 102 sources identified. We found evidence of the influence of many aspects of a school's physical environment on healthy-eating outcomes. The causal loop diagram highlights multilevel and interrelated factors and elucidates the specific roles of design and architecture in encouraging healthy eating within schools. Our review highlighted the gaps in current evidence and identified areas of research needed to refine and expand school architecture and design strategies for addressing healthy eating.